A known electric machine is usable as an alternatingcurrent of direct-current motor or generator and having a rotor surrounded by a stator. A stack or pack of stator plates have a central passage defining an axis and the stack is formed along its inner periphery with an array of grooves parallel to the axis. A stator winding consisting of a plurality of coils is fitted to this stator stack, with the bundles of wire of the coils lying in the grooves so as to surround the rotor when the machine is in use.
The bights of the coils forming the stator winding lie to either axial side of the stator-sheet pack. These winding heads to either side of the pack are typically widened somewhat to an internal diameter somewhat greater than the outer diameter of the rotor so that this rotor may be fitted into the stator from either end. The grooves within the stator-sheet stack are usually lined with insulating material.
As a result of this configuration it is necessary to make the stator coils relatively long. This extra length is needed at the ends in order to bend them outwardly and prevent too tight crimping of the conductors. Thus a considerable quantity of conductive material, usually copper, is employed in the stator winding which serves no useful function, merely increasing cost.
Another difficulty with such prior-art arrangements is that the stator winding is difficult to assemble. The individual windings must be painstakingly laid in place on the stator-sheet stack. Thereafter the ends of the winding must be bent outwardly. This latter operation is usually carried out manually with the aid of a so-called support cage on which the outer peripheries of the stator-winding heads rest. See German offenlegungs-schrift 2,134,523.